1: n-butyllithium With copper (I) cyanide in tetrahydrofuran T=-78 - 0°C; 0.1 h; Inert atmosphere; 2: 1,5-anhydro-4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-2-deoxy-1-tributylstannyl-D-arabino-hex-1-enitol in tetrahydrofuran T=-35 - 20°C; 16 h; Inert atmosphere;